1. Field of the Invention
This invention relates in general to a power protection device. More specifically, the present invention relates to a power protection device capable of preventing over-current, leakage current and surge current at the same time.
2. Description of Related Art
As the technology is developed far beyond our imagination, people count on electrical appliances more and more. For example, computers, washing machines, micro-ovens, air-conditioners, and refrigerators, etc., bring great convenience for people and increase their living quality. However, as the amount of the electricity used increases, the danger also increases. Generally, abnormal electrical phenomena include over-current, leakage current and a surge. Over-current means that the total current used for the appliances is too large for the power lines. The leakage current often occurs in a high humidity environment, such as the bathroom, so that the current flows through the human body to cause an electric shock. For example, a current over 8 mA generally causes an electric shock. A surge means that a high voltage occurs suddenly and temporally, which causes the appliances to be damaged. Conventionally, different power protection devices corresponding to respective abnormal phenomena of the power source arc individually developed. For example, some extension outlets have a surge protection device with a fuse to prevent the appliance from being damaged. In addition, regarding the over-current protection, a fuse, a mechanical over-current switch, or a device using a detector circuit are provided. However, the conventional power protection device can only provide one function to solve one of the aforementioned problems. To prevent the different abnormal phenomena, a plurality of protection devices with different functions have to be purchased, so that the purchase cost increases and the difficulty for building the power protection system also increases.